Control device for power actuated lifts on tractors



Feb. 6, 1951 H. P. CORDES 2,540,429

CONTROL DEVICE FOR POWER ACTUATED LIFTS 0N TRACTORS Filed June 6, 1947 INVENTOR.

J-C. R Cordes Patented Feb. 6, 1951 UNITED STATES PATENT OFFICE CONTROL DEVICE FOR POWER AGTUATED LIFTS N IR-ACTORS 3 Claims.

This invention is directed to, and it is an object to provide, a novel control device for tractors which include a selectively vertically adjustable, hydraulically power actuated lift for connection in draft relation to an earth working implement; lifts of this type being difficult to maintain at the point of initial vertical setting, and the present device functioning to automatically accomplish such desirable result.

Another object of the invention is to provide a control device, for the purpose described, which is responsiv to undesired up-or-down movement of the earth working implement relative to said point of initial vertical setting thereof; response of the device to such movement being imparted to the lift control lever, which the tractor includes, in a manner to adjust said lever to an extent to cause the power lift to return the implement to said point of initial vertical setting.

An additional object of the invention is to provide a control device, as above, for a tractor having a power lift which includes a power actuated lift arm and a hand lever which causes the power means to regulate the position of such lift arm, both the lift arm and hand lever being swingable in a longitudinal vertical plane, and the control device being connected between the same.

A further object of the invention is to provide a control device, as in the preceding paragraph, which includes a push-pull unit, having an adjustable friction, slip connection therein, operative to impart motion of the lift arm to the hand lever, but permitting the hand lever to be manually operated or set independent of the lift arm.

A further object of the invention is to provide a simple, practical, convenient, and easy to install control device for power actuated lifts on tractors, and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by mean of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

Fig. l is a side elevation of the control device as mounted on a tractor.

Fig. 2 is an enlarged side elevation of such device, detached.

Fig. 3 is a fragmentary elevation of the adjustable friction clamp which cooperates with the control rod between the latter and the bracket attached to the power actuated lift arm.

Fig. 4 is a fragmentary plan view of the conend of the control rod to the hand lever on the tractor.

Referring now more particularly to the characters of reference on the drawings, the contr l device is especially designed for use in connection with a tractor I which includes, between the transversely spaced rear wheels 2, a hydraulically actuated cross shaft 3 having a radial and rearwardly projecting lift arm 4 fixed thereon.

The lift arm 4, which is raised or lowered by actuation of the cross shaft 3, is pivotally connected at its outer end to the upper end of a link 5 which extends rearwardly and downwardly to one of the draft links 6 of the power lift. Such power lift also includes a top stabilizer link I and an upstanding tool mounting frame 8 pivotally connected between the links 8 and I, the latter being vertically swingable with the frame 8 to adjust the vertical position of an earth working implement 9 carried by said frame 8.

Ahead of the lift arm 4, and in generally longitudinal alinement therewith, the tractor includes a hand lever l0 working in cooperation with a guide quadrant Ii. The hand lever in is movable forwardly or rearwardly to cause actuation of certain hydraulic mechanism in the tractor to effect rotation of the shaft 3 so as to cause lowering or raising, respectively, of the arm I, and consequently corresponding motion of the implement 9.

In normal operation of the tractor the operator adjusts the hand lever Ill until the described power actuated lift, to which the implement I is connected in draft relation, is disposed at a desired point of initial vertical setting. However, on certain tractors the hydraulic mechanism, though initially set by the hand lever l0, tends to cause or permit creeping of the power lift either upwardly or downwardly, thus failing to maintain the desired point of initial vertical setting of the implement 9.

To overcome this result, and to automatically maintain such initial setting of the implement, this invention provides the following control device:

A rigid control rod l2 extends lengthwise of the tractor between the upper end portion of the hand lever II and the rear end of the poweractuated, lift arm 4, being connected to these parts as follows:

At its forward end the control rod I2 is fitted with a universal connection II, which includes a cross bolt I 4 extending through a U-clamp l5.

n ti de che ap d to secure the f rw r M This U-ciamp engages about the hand lever ll and is fixed thereto by tightening of said cross bolt it.

The control rod II and rear end of the lift arm 6 are coupled together by an adjustable friction. slip connection, indicated generally at It. This connection comprises an upstanding bracket ll rigidly secured, at its lower end, to the arm 4 by a cross bolt II which extends through a hole it in said bracket. Above the hole It the bracket I? is formed'with an adjustable friction clamp ll, through which the control red I! slidably engages; said clamp including spaced-apart ears ll connected by a cross bolt 22 which extends beyond the ears some distance on one side and is there fitted with a threaded-on finger nut 23. A compression spring II surrounds the bolt 22 between the nut II and one of the ears fl, wherebz adjustment of the finger nut it increases or decreasesthefrictionortensionofaclampfl on therod It.

With the above described control device mounted on a tractor, as shown, the operator sets the hand lever II to effect adjustment of the implement I to the desired point of initial vertical setting; such motion of the hand lever II, and consequent motion of the control rod l2, being accomplished independently of the lift arm I, by reason of the fact that said rod then slides through the clamp ll of the adjustable friction, slip connection ll.

Thereafter, if-the implement I creeps up or down relative to its point of initial vertical setting with corresponding motion of the lift arm 4, such motion is imparted through the connection II to the control rod II, which in turn moves the hand lever I. in a direction to cause compensating actuation of the power lift to return the implement I to said point.

When the control device functions, automatically. to accomplish the above result, the control rod I! does not slip through the adjustable clamp 20, for the reason that the resistance to sliding ofsaidrodthroughtheclampisgreaterthan the resistance of the hand lever to motion.

It will thus be seen that once the operator sets 5 the hand lever II to obtain a predetermined working depth of the implement t, the control device thereafter automatically. and with quick response, resets the lever ll, one way or the other, to the extent n to compensate for the misadjuslment. In addition to the above described function, the control device has a further purpose, as follows: 1

A pair ofadjustable stop collars II and it are mounted on the control red I! on opposite sides of the clamp II; such collars serving as a means to automatically limit the bottom position and top position of the power lift and suspended earth working tool.

Whcntheoperatorshiftsthehandlever il forwardly a certain distance the stop ll will abut the clamp 20, thus preventirw further movement in such direction of the control rod and lever, and in turn limiting the bottom position to which the earth working implement 0 may be lowered. Similarly, when the operator shifts the hand lever in a direction sufilcient to engage the stop It with the clamp, the top position of the power lift is thus effectively limited.

From the foregoing description it will be readily seen that there has been produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device. still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful. and upon which Letters Patent are desired:

1. In a lift means which includes a power operated shaft and a radially extending lift arm fixed at its inner end to the shaft and operated thereby and means to control the application of power to the shaft, such latter means comprising in part an operating lever; means to eifect movement of the lever upon movement of the am, such last named means comprising a rigid control rod pivoted to the lever, and an adjustable friction slip connection between the rod and the arm adjacent its outer end.

2. A structure as in claim 1 in which the adjustable friction slip connection comprises an upstanding bracket fixed on the arm adjacent its outer end and an adjustable friction clamp fixed on the bracket and embracing and frictionaily engaging the control rod.

3. A structure as in claim 2 in which the clamp includes a pair of outer spaced apart ears, a cross bolt projecting through said cars, a nut threaded on the outer end of the bolt, and a compression spring interposed between the nut and the adjacent ear.

HENRY P. CORDEB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATM'TB Number Name Date 419,874 Parkin Jan. 21, 1890 1,627,568 Martin May 10, 1927 2,288,258 Brown June 16, 1942 2,311,516 Brown Rb. 16, 1843 2,427,871 Mott Sept. 23, 1947 

